The present invention generally relates to a modular storage server architecture for retrieving data in response to user access requests. In particular, the invention relates to a server architecture in which data is dynamically distributed over a plurality of disks, a plurality of processors are assigned to particular disks, and data access requests are assigned to particular processors in order to provide good data access performance and server fault tolerance.
A storage server allows users to efficiently retrieve information from large volumes of data stored on a plurality of disks and secondary storage (e.g., magnetic tape or an optical-disk jukebox). For example, a video server is a storage server that accepts user requests to view a particular movie from a video library, retrieves the requested program from disk, and delivers the program to the appropriate user(s). Such a video server is disclosed in U.S. Pat. No. 5,671,377, entitled “System For Supplying Streams Of Data To Multiple Users By Distributing A Data Stream To Multiple Processors And Enabling Each User To Manipulate Supplied Data Stream” issued to Bleidt et al. on Sep. 23, 1997.
The foregoing storage server employs one or more processors that access data that is stored across an array of disk drives using fault tolerant storage technique such as RAID (Redundant Array of Inexpensive Disks). While such architectures provide uniform non-blocking access to all of the data stored on the disk drives, they do not facilitate a modular architecture. Since data is striped across all of the disk drives in the array, adding or removing disk drives to/from the server requires that all of the data be re-striped across the new set of disk drives. Because the servers are not modular, it is therefore inconvenient to increase or decrease storage capacity by adding or removing disk drives.
There is therefore a need in the art for a storage server architecture that is modular and can acceptably resolve content blocking issues.